Wednesday, October 7, 2015

integration - How prove this 1+qint10x1qxdx=suminftyk=0left(fracqk+1right)k



show that:




1+q10x1qxdx=k=0(qk+1)k(1)




I kown prove following this





10xqxdx=n=0qn(n+1)n+1




note that
10xqx=10eqxln1xdx=n=0qnn!10xnlnn1xdx



let ln1x=t10xnlnn1xdx=0e(n+1)ttndt=Γ(n+1)(n+1)n+1


so





10xqxdx=n=0qn(n+1)n+1




But this (1) I can't prove it,Thank you everyone.


Answer



The proof goes along the same lines
10x1qxdx=10xeqxdx=10xn=0(qxlnx1)nn!dx=n=0qnn!10xn+1lnnx1dx{lnx1=t}=n=0qnn!0+e(n+1)ttn(et)dt=n=0qnn!0e(n+2)ttndt{(n+2)t=s}=n=0qnn!0es(n+2)nsn(n+2)1ds=n=0qn(n+2)n+1


Thus

1+q10x1qxdx=1+qn=0qn(n+2)n+1=1+n=0qn+1(n+2)n+1{k=n+1}=q0(0+1)0+k=1qk(k+1)k=k=0(qk+1)k


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